JP2003161350A - Planetary roller speed changer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost planetary roller speed changer with excellent rotation accuracy capable of easily preventing irregularities in rotation deriving from displacement between a revolution shaft of planetary roller and a rotation shaft of a carrier. <P>SOLUTION: Through holes (3j and 3i) opened on the both sides of a carrier 3 are formed at the center of the carrier 3. While an end of an output shaft 4 is fitted and fixed to the opening on the output shaft side, an input shaft 1 is freely rotatably inserted into the opening of the input shaft side. By this configuration, the input shaft 1 and the output shaft 4 can be easily centered, thus preventing irregularities in rotation of the output shaft 4. Since the number of part items for centering the input shaft 1 and the output shaft 4 is small, and assembling becomes easy, the reduction of the product cost can be achieved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary roller type transmission, and more particularly to a planetary roller type transmission capable of improving the rotational accuracy of the transmission and suppressing fluctuations in output rotational speed.

[0002]

2. Description of the Related Art In a planetary roller type transmission (traction drive), a fixed ring is generally arranged around an input shaft (sun shaft), and a plurality of planetary rollers are provided between the input shaft and the fixed ring. Are arranged so as to be in rolling contact with both of them, and each of the planetary rollers is rotatably supported by the carrier. In this structure, by rotating the input shaft, each planetary roller rotates and revolves, and the carrier that rotatably supports them rotates (rotates). By taking out the rotation of the carrier to the outside through the output shaft, the rotation given to the input shaft is decelerated and taken out.

FIGS. 3 and 4 show an example of the construction of a conventional traction drive type planetary roller type transmission. 3 is an axial sectional view of the planetary roller type transmission, and FIG. 4 is its XX section.
It is sectional drawing of the axis orthogonal direction cut | disconnected by the surface.

In this example, a motor 24 is used as a power source, and an output shaft of the motor 24 is an input shaft (sun shaft) 11 of a planetary roller type transmission. A fixed ring 20 is fixed around the input shaft 11 concentrically to the input shaft 11 with respect to the housing main body 21a, and an annular space is formed between the fixed ring 20 and the input shaft 11. The annular space is sealed by a housing lid 21b, and a plurality of planet rollers are provided in the annular space so as to make rolling contact with both the outer peripheral surface of the input shaft 11 and the inner peripheral surface of the fixed ring 20 in a pressure contact state via traction oil. 12 are arranged. Each planet roller 12 is rotatably supported by a common carrier 13, and the carrier 13 has the output shaft 1
4 is fixed by press fitting into the output shaft fitting hole 13j. The output shaft 14 is rotatably fixed to the housing body 21a by the rolling bearings 22 and 22 and is restricted from moving in the axial direction.

As shown in FIG. 4, the fixed ring 20 and the input shaft 1
Each planet roller 12 arranged in the annular space between the
It has a hollow ring shape and is rotatably supported by a columnar portion 13b provided so as to project from the disc-shaped portion 13a of the carrier 13. The columnar portion 13b of the carrier 13 has a shape substantially along the outer diameter of the planetary rollers 12, and supports each planetary roller 12 on its outer peripheral surface in a freely rotatable manner. Carrier 1 by the revolution of each planetary roller 12
The rotation of 3 is fitted and fixed to the carrier 13.
4 is transmitted.

In the above structure, by rotating the input shaft (sun shaft) 11, the rotation of the input shaft 1 is prevented.
1 is transmitted by traction drive to each planetary roller 12 sandwiched between the fixed wheel 20 and the fixed wheel 20, and these planetary rollers 12 revolve around the input shaft 11 while rotating, thereby causing the carrier 13 to rotate. The rotation of the input shaft 11 is transmitted to the output shaft 14 fixed to the carrier 13 after being decelerated.

By the way, in the planetary roller type transmission as described above, in an application requiring precise output control such as a plate making machine, fluctuations in the output of the transmission (changes in the rotational angular velocity of the output shaft, in other words, in the output shaft). Is required, that is, the rotation accuracy of the transmission is high.

One of the causes of the uneven rotation of the output shaft 14 of the planetary roller type transmission is the center axis of rotation of the output shaft 14 integrated with the carrier 13 and each planet roller rotatably supported by the carrier 13. 12 revolution center axes (ie input shaft 1
The center axis of revolution of the planetary roller 12 is eccentric.

In order to prevent such uneven rotation of the output shaft 14 and improve the rotation accuracy, the dimensional accuracy and assembly accuracy of the components used in the conventional planetary roller transmission have been emphasized. . Specifically, a method of improving the dimensions and fitting accuracy of the planetary roller unit and the housing body 21a to which the unit is attached has been mainly used.

[0010]

However, in the conventional measures for improving the rotation accuracy in the planetary roller type transmission as described above, since the number of parts involved in the rotation unevenness is large, the required dimensional accuracy is obtained. Not only is it difficult, but the cost of parts is high.

That is, the dimensional accuracy of each planetary roller, the dimensional accuracy of a fixed ring with which the planetary roller is in contact, the fitting accuracy of the fixed ring and the housing main body, the fitting accuracy of the rolling bearing that supports the housing main body and the output shaft, etc. Since it affects the rotation (output) of the roller type transmission, it is difficult to keep all of these dimensional accuracy and assembly accuracy within the standard. In addition, the processing of these parts that require dimensional accuracy is
It will also increase the cost.

Further, the structure of the conventional planetary roller type transmission has a drawback that the center of the input shaft and the center of the output shaft are easily displaced by an external force.

The planetary roller type transmission in which this problem occurs is not limited to the structure in which the outer diameter of the planetary roller is supported by the columnar portion projecting from the carrier as described above, and the hollow portion of the planetary roller is used as the carrier. This is a common problem for other types of planetary roller transmissions, such as bearings that are supported by pins protruding from the transmission.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to easily suppress the uneven rotation due to the deviation between the revolution axis of the planetary roller and the rotation axis of the carrier, and to rotate at a low cost. It is an object of the present invention to provide a planetary roller type transmission with high accuracy.

[0015]

In order to achieve the above-mentioned object, the invention according to claim 1 provides an input shaft to which input rotation is applied, a fixed ring arranged around the input shaft, and these. A plurality of planet rollers arranged between the input shaft and the fixed wheel and in rolling contact with them, and a disk-shaped carrier that rotatably supports each planet roller and that rotates by the revolution of each planet roller. In a planetary roller type transmission that is connected to this carrier and has an output shaft that rotates integrally, a through hole that opens on both the front and back sides of the carrier is formed at the center of the carrier, and the opening on one surface side thereof is formed. The output shaft is fitted and fixed to the input shaft, and the input shaft is rotatably inserted and supported in the opening on the other surface side.

Here, as the through-hole in the present invention,
In addition to the straight holes having the same opening diameter, a step may be provided in the middle of the holes so that the opening diameters are different.

Further, in the present invention, it is possible to adopt a structure in which a slide bearing or a rolling bearing is arranged between the input shaft and the through hole (claim 2).

According to the present invention, a through hole that opens on both front and back sides is formed at the center of a carrier that rotatably supports a planetary roller, and an output shaft and an input shaft are inserted on both sides of the through hole, respectively. This is intended to facilitate the centering of the output shaft and the input shaft and achieve the intended purpose.

That is, in the present invention, a through hole is formed in the carrier, the output shaft is fitted and fixed in one opening, and the input shaft is rotatably inserted in the other opening. When the through hole is a straight hole having the same opening diameter for both the input and output shafts, it is natural that the input and output shafts inserted or fitted therein can be extremely easily centered. Further, even when both opening diameters are made different according to the sizes of the input / output shafts (through holes having stepped portions), centering can be performed easily and accurately by the so-called inlay structure.

The only parts that require a high degree of dimensional accuracy to match the output shaft and input shaft rotation center axes are the outer diameter of the output shaft and input shaft, and the through hole of the carrier into which they are fitted. Moreover, since the shape of the portion that requires dimensional accuracy is simple, it is easy to obtain high accuracy, and the cost can be significantly reduced.

Further, the planetary roller type transmission having this structure is
Since the tip of the input shaft is supported by the center of rotation of the carrier that fits and fixes the output shaft, there is an advantage that the center of rotation of the output shaft and the center of rotation of the input shaft do not easily shift even when external force is applied. is there.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an axial sectional view of a planetary roller transmission according to a first embodiment of the present invention. The planetary roller transmission according to the embodiment of the present invention also uses the motor 24 as a power source, and the output shaft of the motor 24 also serves as the input shaft (sun shaft) 1 of the planetary roller transmission, as in the conventional example. 1 illustrates a structural transmission.

In the planetary roller type transmission according to the present embodiment as well, the fixed ring 20 is fixed to the housing main body 21a around the input shaft (sun shaft) 1 concentrically with respect to the input shaft 1. An annular space is formed between the fixed ring 20 and the input shaft 1. The annular space is sealed by a housing lid 21b, and a plurality of planet rollers are arranged in the annular space so as to make rolling contact with both the outer peripheral surface of the input shaft 1 and the inner peripheral surface of the fixed ring 20 in a pressure contact state via traction oil. 2 are arranged. Each planet roller 2 is rotatably supported by a common carrier 3, and an output shaft 4 is fixed to the carrier 3 by press fitting into an output shaft fitting hole 3j. The output shaft 4 is rotatably fixed to the housing body 21a by the rolling bearings 22 and 22, and is restricted from moving in the axial direction.

Each planetary roller 2 arranged in the annular space between the fixed ring 20 and the input shaft 1 has a hollow ring shape and is provided so as to project from the disk-shaped portion 3 a of the carrier 3. It is rotatably supported by the columnar portion 3b.
As described in the conventional example, the columnar portion 3b of the carrier 3 has a shape that is substantially along the outer diameter of the planetary rollers 2, supports each planetary roller 2 in a freely rotatable manner, and has the input shaft 1 as the center. It also supports the revolution of these planetary rollers 2. The rotation of the carrier 3 due to the revolution of the planetary rollers 2 is transmitted to the output shaft 4 through the disk-shaped portion 3a. With the above configuration, the rotation of the motor 24 is reduced by this planetary roller type transmission and then transmitted to the output shaft 4.

The feature of the planetary roller type transmission in this embodiment is that through holes (3j, 3i) having different diameters for the output shaft 4 and the input shaft 1 which are opened at both sides of the carrier 3 at the rotation center of the carrier 3 are provided. Is provided. That is,
A step portion 3h is provided in the middle of the through holes (3j, 3i), the opening diameter on the output shaft 4 side is formed larger than the opening diameter on the input shaft 1 side, and the large diameter portion on the output shaft 4 side is formed. Is an output shaft fitting hole 3j into which the end of the output shaft 4 is press-fitted, and a small-diameter portion on the input shaft 1 side is an input shaft fitting hole 3i into which the input shaft 1 is rotatably inserted. Has been done. In this way, holes are formed through both side surfaces of the carrier 3 which is a single component, and these through holes are formed through the output shaft fitting hole 3j and the input shaft fitting hole 3j.
Since i is set to i, the centering of the output shaft 4 and the input shaft 1 can be made highly accurate by a so-called inlay structure.

The fitting portion between the output shaft 4 and the output shaft fitting hole 3j is integrated by press-fitting and fixing as in the conventional case.
In addition, the fitting portion between the input shaft 1 and the input shaft fitting hole 3i adopts a sliding bearing structure, and a predetermined gap is formed between the inserted input shaft 1 and the input shaft fitting hole 3i. Has been
The input shaft 1 is rotatable with respect to the carrier 3. Here, in order to make the input shaft fitting hole 3i function as a plain bearing, the material of the carrier 3 is preferably a material different from the input shaft 1, for example, brass or the like when the input shaft 1 is iron. be able to.

The output shaft 4 and the input shaft 1 fitted in the output shaft fitting hole 3j and the input shaft fitting hole 3i, respectively, are arranged with a slight distance between their tip portions. To be done. With these structures, it is possible to prevent the output shaft 4 and the input shaft 1 from interfering with each other, and the output shaft 4 (carrier 3) and the input shaft 1 can rotate freely while making their rotation center axes coincide with each other. it can.

According to the above embodiments, the output shaft 4 and the input shaft 1 of the planetary roller type transmission can be easily aligned with each other, and the revolution axis of the planetary roller 2 and the carrier 3 can be easily matched.
It is possible to suppress uneven rotation caused by the deviation of the rotation axis. Moreover, the only part that requires a high degree of dimensional accuracy is the outer dimensions of the output shaft 4 and the input shaft 1 and the output shaft fitting hole 3j and the input shaft fitting hole 3i into which they are fitted, and is involved in centering. The number of parts used is small. Furthermore, since the tip of the input shaft 1 is rotatably supported about the rotation center of the carrier 3 to which the output shaft 4 is fitted and fixed, the output shaft 4 and the input shaft 1 can be rotated even when external force is applied. The structure is such that the center axis of rotation does not easily shift.

Next, a second embodiment will be described. FIG. 2 is an axial cross-sectional view of a planetary roller transmission showing a second embodiment. The basic configuration of this example shown in FIG. 2 is similar to that of the previous embodiment, except that the opening diameter of the carrier 3 on the input shaft 1 side is made larger than that on the output shaft 4 side. The point is that the needle roller bearing 23 is arranged at the fitting portion with the shaft 1.

In this way, the input shaft 1 has the needle roller bearing 23.
By being supported by the through hole of the carrier 3 via
The material of the carrier 3 can be arbitrarily selected, and the degree of freedom in its design can be improved.

Incidentally, instead of the needle roller bearing 23 used in the above-mentioned embodiment, other types of ball bearings or roller bearings such as roller bearings may be adopted. The same effect can be achieved even if the sliding bearing is adopted.

In the above two embodiments, the planetary roller type transmission having the structure in which the outer diameter of the planetary roller 2 is supported by the columnar portion 3b protruding from the carrier 3 has been shown. However, the present invention has a hollow portion of the planetary roller. It is needless to say that the present invention is equally applicable to other types of planetary roller type transmissions, such as supporting a pin with a pin protruding from the carrier.

[0033]

As described in detail above, according to the present invention,
A through hole is formed in the carrier, the output shaft is fitted and fixed in one opening, and the input shaft is rotatably inserted in the other opening. Can be very easily centered. With this configuration, it is possible to suppress the deviation of the rotation centers of the output shaft and the input shaft due to the eccentricity of the revolution center axis of the planetary roller, and prevent the rotation unevenness of the planetary roller transmission. Moreover, since the number of parts involved in centering the input shaft and the output shaft is small, the planetary roller transmission can be easily assembled,
Product cost can be reduced.

Further, if the structure in which the input shaft is supported in the through hole of the carrier through the rolling bearing and the sliding bearing is adopted,
The material of the carrier can be arbitrarily selected, and the degree of freedom in its design can be improved.

Since the tip of the input shaft is rotatably supported by the carrier to which the output shaft is fitted and fixed,
Even when an external force is applied, the center axis of rotation of the output shaft and the input shaft do not easily shift.

[Brief description of drawings]

FIG. 1 is an axial cross-sectional view of a planetary roller transmission according to a first embodiment of the present invention.

FIG. 2 is an axial cross-sectional view of a planetary roller transmission according to a second embodiment of the present invention.

FIG. 3 is an axial sectional view of a conventional planetary roller transmission.

FIG. 4 is a sectional view taken along line XX of FIG.

[Explanation of symbols]

1,11 Input axis (Sun axis) 2,12 Planetary roller 3,13 career 3a, 13a disk-shaped part 3b, 13b columnar section 3h step 3i Input shaft fitting hole 3j, 13j Output shaft fitting hole 4,14 Output shaft 20 fixed wheels 21a housing body 21b housing lid 22 Rolling bearing 23 Needle roller bearings 24 motor

Claims (2)

[Claims] 1. An input shaft to which an input rotation is given, a fixed ring arranged around the input shaft, and a plurality of planet rollers arranged between the input shaft and the fixed ring and rollingly contacting both of them. , A planetary roller type speed changer comprising a disk-shaped carrier that rotatably supports each planetary roller and that rotates by the revolution of each planetary roller, and an output shaft that is connected to this carrier and rotates integrally. In the machine, at the center of the carrier, a through hole that opens on both front and back sides is formed, and the output shaft is fitted and fixed to the opening on one surface side of the carrier, and the through hole is formed on the opening of the other surface side. A planetary roller transmission in which an input shaft is rotatably inserted and supported. 2. The planetary roller type transmission according to claim 1, wherein a sliding bearing or a rolling bearing is interposed between the input shaft and the through hole.